Cryptology ePrint Archive: BibTeX Citation of Report 2009/285

@misc{cryptoeprint:2009:285,
    author = {Damien Stehlé, Ron Steinfeld, Keisuke Tanaka, Keita Xagawa},
    title = {Efficient Public Key Encryption Based on Ideal Lattices},
    howpublished = {Cryptology ePrint Archive, Report 2009/285},
    year = {2009},
    note = {\url{http://eprint.iacr.org/}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.